TM 55-1510-221 -10
tlons. activate ICE VANES if the temperature is below
Use normal procedures in Section II.
avoid taxiing over sandy terrain to
minimize propeller damage and engine deterioration that
results from Impingement of sand and gravel. During hot
weather operation. use minimum braking action to prevent
Use normal procedures in Section II.
Avoid taking off in the wake of another alrcraft of the
runway surface is sandy or dusty.
f. During Flight. Use normal procedures in Section
g. Descent. Use normal procedures in Section II.
h. Landing. Use normal procedures in Section II.
i. Engine Shutdown. Use normal procedures in
During hot weather. if fuel tanks are completely
filled. fuel expansion may cause overflow,
thereby creating a fire hazard.
j. Before Leaving Aircraft. Use normal procedures in
Section II. Take extreme care to prevent sand or dust from
entering the fuel and oil system during servicing. During
hot weather. release the brake immediately after installing
wheel chocks to prevent brake disc warpage.
8-71. TURBULENCE AND THUNDERSTORM
Due to the comparatively light wing loading,
control in severe turbulence and thunderstorms
Since turbulence imposes heavy
loads on the aircraft structure. make all
necessary changes in aircraft attitude with the
least amount of control pressures to avoid
excessive loads on the aircrafts structure.
Thunderstorms and areas of severe turbulence should be
If such areas are to be penetrated. it will be
necessary to counter rapid changes in attitude and accept
major Indicated altitude variations. Penetration should be
of an altitude which provides adequate maneuvering
margins as a loss or gain of several thousand feet of
altitude may be expected. The recommended penetration
speed in severe turbulence is 158 KIAS. Pitch attitude and
constant power settings are vital to proper flight technique.
Establish recommended penetration speed and proper
attitude prior to entering turbulent air to minimize most
difficulties. False Indications by the pressure Instruments
due to barometric pressure variations within the storm
make them unreliable. Maintaining a pre-established
attitude will result in a fairly constant airspeed. Turn
cockpit and cabin lights on to minimize the blinding effects
of lighting. Do not use autopilot altitude hold. Maintaln
constant power settings and pitch attitude regardless of
airspeed or altitude indications. Concentrate on maintaining
a level attitude by reference to the Flight Director/Attitude
Indicator. Maintain original heading. Maker no turns
unless absolutely necessary.
8-72. ICE AND RAIN (TYPICAL).
While in icing conditions. if there is an
unexplained 30% increase of torque needed
to maintain airspeed in level flight, a
cumulative total of two or more inches of ice
accumulation on the wing, an unexplained
decrease of 15 knots IAS. or an unexplained
deviation between pilots and copilots
airspeed indicators, the icing environment
should be exited as soon as practicable. Ice
accumulation on the pitot tube assemblies
could cause a complete loss of airspeed
The following conditions indicate a possible
accumulation of ice on the pitot tube assemblies and
unprotected aIrplane surfaces.
if any of these conditions
are observed. the icing environment should be exited as
soon as practicable.
(1) Total ice accumulation of two inches or more on
the wing surfaces. Determination of ice thickness can be
accomplished by summing the estimated ice thickness on
the wing prior to each pneumatic boot deice cycle (e.g. four
cycles of minimum recommended 1/2-inch accumulation.
(2) A 30 percent Increase in torque per engine
required to maintain a desired airspeed in level flight (not
to exceed 85 percent torque) when operating at
recommended holding/loiter speed.
(3) A decrease in Indicated airspeed of 15 knots
after entering the icing condition (not slower than 1.4
power off stall speed) if maintaining original power setting
in Ievel flight. This can be determined by comparing pre-